Torque sensitive reversible motion actuator



June 19, 1956 H. s. DODGE TORQUE SENSITIVE REVERSIBLE MOTION ACTUATORFiled Aug. 50, 1954 3 Sheets-Sheet 1 i &

IN V EN TOR.

Howard 6. Dodge H. G. DODGE June 19, 1956 TORQUE SENSITIVE REVERSIBLEMOTION ACTUATOR Filed Aug. 30, 1954 5 Sheets-Sheet 2 INVENTOR. Haward 6.Dodge BY June 19, 1956 H. s. DODGE 2,751,219 TORQUE SENSITIVE REVERSIBLEMOTION ACTUATOR Filed Aug. 30, 1954 s Sheets-Sheet s fa wara G fioc/ge2,751,219 Patented June 19, 1956 ice TORQUE SENSITIVE REVERSIBLE MOTIONACTUATOR Howard G. Dodge, College Place, Wash. Application August 30,1954, Serial No. 452,850 2 Claims. (Cl. 268-59) This invention relatesto torque sensitive reversible motion actuators for producing a desiredmovement and halting the movement when the torque exceeds that normallyrequired and reversing the actuator upon subsequent operation thereof.

Although not necessarily limited thereto the present device is admirablysuited for the operation of a vertically movable garage door wherein amotor driven endless belt is trained about pulleys and is suitablysecured to the door intermediate the pulleys so that actuation of thebelt will cause the door to be moved to open and closed positions. Thepresent application is a continuation in part of my copendingapplication-Serial No. 353,636, filed May 7, 1953, and entitled GarageDoor Opener, now abandoned.

Among other advantages and features this invention provides meanswhereby a door such as a garage door may be opened and closed by anautomatically reversible torque sensitive motion actuator which isadapted to halt operation upon increase of torque at the motor exceedingthat required to open and close the door, thus precluding thepossibility of injury to a person or mutilation of an object which maybe inadvertently disposed in the path of movement of the door.

Many types of door opening and closing devices have been employed toautomatically operate garage doors, but it has been found to be verydifiicult to devise a garage door operating mechanism whichsubstantially eliminates the possibility of damaging the door mountingand/or actuating mechanism or obstruction which may be disposed in thepath of movement of the door.

With this thought in mind this invention contemplates electricallyactuated door opening and closing means wherein movement of the door isinstigated by closing an electrical circuit through conventionalswitches and relays to actuate an electric motor and provides means foropening the circuit should the torque at the motor increase above thatrequired for opening and closing the door.

It is therefore one object of this invention to provide, for operating agarage door, electrically actuated means designed to halt operation-ofthe door should the torque at the motor exceed the amount required fornormal movements of the door.

Another object of the invention lies in the provision of anautomatically reversible torque sensitive motion actuator whichis'comparatively simple in construction, strong, durable, highlyefiicient and reliable in use, compact, and which may be manufactured ata low cost.

All of the foregoing and other objects of the invention will becomeapparent from a study of the following specification taken in connectionwith the accompanying drawings wherein like characters of. referencedesignate corresponding parts throughout the several views and wherein apreferred form of the invention is shown. It should be understoodhowever that the drawings and description are illustrative only andshould not be construed as limiting the invention except insofar as itis limited by the prior art and the appended claims.

In the accompanying drawings:

Figure 1 is a vertical cross section taken through a garage door and afragmentary portion of a garage having portions broken away forconvenience of illustration;

Figure 2. is a vertical elevation of the improved motion actuatorhaving'its cover removed and upon an enlarged scale;

Figure 3 is a view similar to Figure 2 and showing the motiontransmitting mechanism swiveled by excess torque;

Figure 4 is a vertical view partially in cross section and taken at line4-4 of Figure 2;

Figure 5 is a view taken substantially at line 5-5 of Figure 4 andhaving parts broken away for convenience of illustration; and

Figure 6 is an enlarged view of the catch mechanism for the top of thegarage door.

Figure 7 is a wiring diagram illustrating the electric circuit used.

Referring now in detail to the drawings, Figure 1 discloses portionswhich represent at 10 a garage having a ceiling or other horizontalsupport member 11 disclosed above the door opening 12 formed in one wall10 of the garage. The garage is supplied with a concrete or other typefloor surface 13 and has a vertically moveable closure or door 14supported by mounting means 15 on the wall 10' of the garage. To guidemovement of the upper edge of the door 14 I have disclosed one of a pairof laterally spaced horizontally extending parallel guide rails 16 whichextend inwardly of the garage from the wall having the opening 12, andmoveably carry rollers (not shown) journaled on the door 14.

The motion actuator is indicated in general by the numeral 17 and asseen in Figure l is supplied with a metal or other type housing 18 whichis removable to provide access to the working parts. The actuator issupported from the support member 11. A V-belt pulley 19, disposed in avertical plane, is part of the actuator 17, as will be more fullydescribed hereinafter, and has trained thereabout an endless belt 20which extends forwardly from the pulley 19 and is trained about a secondpulley 21 journaled in any convenient manner upon the wall 10' of thegarage 10 above the opening 12 and midway its width. To provide meansfor applying tension to the belt 20, I provide an idler pulley 22 whichis secured to the ceiling 11 and the belt 20 is trained thereover.

Resiliently or securely fastened to the belt 20 is a connecting link 23which is pivotally secured at 24 to the, upper end of an angular arm 25pivoted at 26 to the door 14. Also secured to the door are a pair ofinwardly extending laterally spaced ears 27, one disposed at each sideof the arm 25 and, which journal the ends of a rod 28 for axialrotation. The rod is provided with a right angle latch arm 29 adapted tocooperate with a latch member 30 anchored to the garage 10 to releasablylatch the door in the closed position. A spring 31 is provided toyieldably hold the latch arm 29 in latching relation to the latch member30 and thus prevent accidental movement of. the door from the closedposition. However, the rod 28 is provided with a radially extendingactuating finger 32 which bears against the arm 25 and is disposed insuch a position that when the arm 25 is pivoted at 26 inwardly of thegarage the rod 28 is axially rotated and the latch arm 29 is moved fromthe full line position to the broken line position shown in Figure 6,thus being released from the member 30 and permitting the door to open.The arm 25 at the end of its movement strikes the rod 28 whichconstitutes a stop for the arm and permits the door to be pulled by thebelt 20 through the link 23. and arm 25.

The subject matter of the present invention is contained' in anautomatically reversible torque sensitive motion actuator indicated inits entirety by the numeral 17 and briefly consists of a reversibleprime mover 33, here shown to be an electric motor, having a motor shaft34 which constitutes a driving shaft. The motor 33 is preferablysupported by the frame 35 of the motion actuator but may be supported atany point found convenient and desirable. Iournaled for rotation uponthe frame 35 I provide a driven shaft 36 which is fixed to and supportsthe pulley 19. Intermediate the driven shaft 36 and the driving shaft 34I provide a swivel mounted motion transmitting mechanism 37 which ishere shown to be a series of belts and pulleys to provide means fortransmitting the rotary motion from the driving shaft 34 to the drivenshaft 36 at a greatly reduced speed.

In this construction the motion transmitting mechanism includes a stubshaft 38 which is anchored at right angles to rockable arm 39 journaledat 40 coaxial with shaft 36. To assist in understanding the invention Idisclose the transmitting mechanism in detail as having a driving shaft34 provided with a relatively small pulley 41 fixed thereon. Journaledfor rotation on shaft 36 in the plane of pulley 41 is a large pulley 42which is ganged with a small pulley 43. A belt 44 is trained about thepulleys 41 and 42. A belt 45 is trained about the pulley 43 and about alarge pulley 46 journaled on the stub shaft 38 and ganged with a smallpulley 47. Still another belt 48 is trained about the small pulley 47and a large pulley 49 fixed to the shaft 36. Thus it will be seen thatrotary motion of driving shaft 34 will impart rotary motion to the shaft36 and therefore will rotate the pulley 19 causing the belt 20 to movethe door 14 to open and closed positions.

The torque at the motor 33 or driving shaft 34 required to move the door14 provides reverse torque at the pulley 49 and therefore the smallpulley 47 endeavors to travel an arcuate path defined from the axis ofshaft 36 and causing the rockable arm 39 to swing from the full lineposition of Figure 2 to the broken line position of Figures 2 and 5 orto the full line position of Figure 3. Since the arm 39 is disposedabove the center of gravity I provide yieldable means 50-50 which areshown to be tension springs that oppose each other and yieldablymaintain the rockable arm 39 in a vertical position. When the torquebecomes great enough to overcome either spring 50 the arm 39 is causedto swivel at 40 according to whichever direction the torque is applied.

The rockable arm 39 is provided with a pair of opposed strikers 51adapted to strike the actuating buttons 52 of normally colsed limitswitches 53 carried by the frame 35. As the torque becomes great enoughto cause the rockable arm 39 to swivel to one side or the order astriker 51 contacts the actuator 52 of its companion switch 53 and opensthe switch thus halting the movement of the garage door.

Inspection of Figure 4 will reveal that the rockable arm 39 is providedwith a right angle undulatory finger 54 which passes intermediate a pairof rockable levers 55 and 56. As the arm 39 rocks to the right, asviewed in Figure 3, the lever 56 is carried by the finger 54 thusstretching the spring 50 while the opposed lever 55 is supported by astop 57 carried by the frame 35. Movement of the arm 39 in the opposeddirection will cause the lever 55 to move therewith and stretch theopposed spring 50.

In Figure 5 it is clearly seen that means are provided at 58 to adjustthe tension of the springs 50 so that sufficient torque may be appliedto shaft 36 to cause the door to open and close without undue rockingmovement of arm 39.

At its lower end the rockable arm 39 is provided with a depending yoke60 which is adapted to strike and actuate a reversing switch 61 carriedby the frame 35. As the rockable arm 39 swivels to the position where itstrikes an actuating button 52 of limit switches 53 or 53' it willsimultaneously actuate the reversing switch 61 so that subsequentoperation of the motion actuator will be in a reverse direction from thedirection of movement present when stopping. Therefore, should thegarage door descend upon the hood or other part of an automobile orother object, the increased torque will cause the actuator to halt andreverse the actuator so that subsequent energizing of the motor 33 willcause the door to raise instead of lower. Obviously the garage door maybe stopped at any point upon striking an obstruction without doingdamage to the door mechanism or the obstruction and therefore providinga very safe and convenient garage door control means.

In theoretical practice it appears that the arm 39 will remain in aposition wherein the striker 51 retains the actuating button 52 in suchposition as to maintain the limit switch 53 or 53 in an open condition.However, in actual practice this is not the case since the springs 50-59tend to return the arm 39 to its normal position when the torque createdby the prime mover 33 is releaved and also the slack or lost motionpresent due to the endless belt 20 permits the arm this return movement.

Associate with the prime mover 33, I employ any one of a number ofconventional wiring circuits preferably using a low voltage secondarycontrol circuit in which the switches 53 and 53 are interposed tocontrol a magnetic relay for selective operation of a primary circuitincluding the prime mover 33 and the reversing switch 61. Since thiscircuit may assume a number of various wiring organizations which arewell known in the art it is not thought necessary to enlarge thistreatise by a detailed disclosure thereof.

The circuit shown in Figure 7 is a typical motor reversing circuitembodying the switches 53, 53 and 61. Such a circuit is shown, althoughin greater detail, in the patent to Steven No. 2,586,273. Other examplesare found in the Johnson Patent No. 2,070,832, and in the ChandlerPatent No. 2,208,119. As is customary in these devices a manuallyoperable main switch 62 is provided.

I have disclosed a motion transmitting mechanism for convenience ofrevealing the invention as having a plurality of belts and pulleys, itwill be understood, however, that gears or other equivalents areencompassed in the term motion transmitting mechanism and the usethereof is envisioned.

Having thus described the invention, what I desire to secure by LettersPatent of the United States is:

1. In a garage door operating mechanism wherein a door is carried by amounting and is movable to open and closed positions by operation of areversible drive mechanism, a control device for the drive mechanismcomprising a rockable arm interposed in said drive mechanism and urgedto swing in one direction from a mid point in response to torquetransmitted by the drive mechanism when it is moving in one directionand urged to swing in the opposite direction in response to torquetransmitted by the drive mechanism when it is moving in the oppositedirection, a pair of spring pressed members engaging the rocker arm atthe mid point, one member opposing movement of the arm in one directionfrom mid point, means restraining said member from following the armwhen it moves in the opposite direction from said mid point, the othermember opposing movement of the arm from said mid point in said oppositedirection, and means restraining the last named member from followingthe arm when the arm moves in said one direction and is opposed by thefirst named member.

2. A mechanism for operating doors such as garage doors, comprising areversible electric motor, an electric circuit operably connected tosaid motor for energizing and controlling it, a driving shaft rotatableby said motor, a driven shaft, a pivotally mounted motion transmittingmechanism operably connecting said shafts and operative by torquebetween said shafts to move about its pivotal axis, said mechanismincluding a rockable arm movable to and fro, a pair of spring pressedmembers engaging said rocker arm, one member opposing movement of thearm in one direction from a normal position, means restraining saidmember from following the arm when it moves in the opposite directionfrom the normal position, the other member opposing movement of the armfrom normal position in said opposite direction, means restraining thelast named member from following the arm when the arm moves in said onedirection against the opposition of the first named member, two normallyclosed limit switches in said circuit, each adapted to open the circuitand deenergize the motor, one switch being in the path of movement ofthe arm from normal position against the opposition of one of saidmembers, the other switch being in the path of movement of the arm fromnormal position against the opposition of the other member, a reversingswitch in the circuit operable to reverse the direction of rotation ofsaid motor, and means on said arm actuating the reversing switch whenthe arm moves to engage either of the first named switches.

Chandler July 16, 1940 Wilcox Apr. 20, 1954

